I just returned from a 4 day trip, riding and camping out in the Driftless area of Wisconsin.
I've decided that I would like to upgrade my sleeping bag and pad. I'm looking for recommendations for a sleeping bag that would be good to 45 F or so, pack very small, but be large enough for an average size adult to have some room to shift around in. Budget = $ 150 ? Also looking for a pad that's is better/thicker than my 1.5" REI "Thermarest" type pad. [I need to sleep on my side to keep my airway open while I sleep, as I have borderline sleep apnea, so a thicker pad would help], but it would also need to pack small.
I've ruled out the hammock type sleepers, because there is not always trees to hang them from at open camp sites that I visit.
Many choices, I will point out what and why. First, almost all my bags are mummy style and have a hood, are synthetic. I use self inflating mattress and carry a small hand pump that doubles as a bellows for starting a camp fire. I also carry a reflecting blanket that goes under the mattress, ideal place is between the bag and mattress but almost impossible to stay in one place. The largest part of heat loss in a sleeping bag is through the ground and your head. Thermarest etc, offers a r value of around 3 at best, problem is lying on your side compresses it reducing R value. The reflecting blanket is usually equal to twice the R value of the mattress or about R 7.
If your bag doesn't come with a compression sack, buy one, my 40'F mummy bag will fit into a 1 gallon pail. Be aware, never use a reflecting blanket on top of your bag, it traps moisture and eventually you will wake up possibly suffering from mild hypothermia, due to the fact your bag has lost insulation value from the moisture. Plan on bringing polypropylene top and bottom to add insulation value when your in temperatures below what your bag is rated for. A bags rating is usually taking into consideration that you are using it in a tent. So a 40'F bag is really rated at 50'F with the addition of a tent= 40'F . When buying a bag, look for YKK two way zippers, that way if you start out too hot you can zip the bottom open, closing when the temperature drops.
As to your position of sleeping, I have always taken a extra stuff sack, put my socks, top, pants and whatever extra clothing I had along to form a pillow, one benefit is your head warms it up during the night, so if you pack it in order of dressing, can be a pleasant
The difference between a good bag and a crap bag, a crap bag has no baffle for the zipper, is a one way non YKK that is hard to operate.
I have bags rated down to -30'F, also have both down and synthetic, I have also been caught with my 40'F bag and it hit 32'F with high winds , had everything with me on me , not much sleep. You can also get synthetic liners for some bags, which gives about a 10'F increase to the bag, make sure there are ties or means of fastening this to the bag, advantage is you can pack the liner separate and as a option for temperature control.